Transient radio sources: Input to the SKA

Supervisors: Gerry Doyle & Gavin Ramsay

There is growing evidence that some radio flares/bursts can occur as a result of narrow band, rapid, intense and highly polarized emission (up to 100%), that are observed especially at lower frequency (<4 GHz). For their extreme characteristics, this kind of radio bursts have generally been interpreted as the result of coherent emission mechanisms.

Coherent burst emission has been observed in different classes of stellar objects (RS CVns, Flares stars, Brown dwarfs, Chemically Peculiar stars), all having as common ingredients a strong and also, but not necessarily, variable magnetic field and a source of energetic particles.

With the new Australia Telescope National Facility and Expanded Very Large Array setups, there are several key unanswered questions regarding coherent stellar bursts/flares that we would like to address. These new instruments combine the positive traits of previous observations using the VLA and Arecibo, while easily exceeding the performance of either instrument. We are currently in the process of obtaining high cadence, high spectral resolution over a large frequency range for a sample of active RS CVn systems, flare stars and ultracool dwarfs.

We aim to address questions such as "What is the nature of coherent emission in different stellar systems?", "What is the relation of coherent flaring to flaring in other wavelength regions?", "What do analyses of the burst/flare structure in the frequency and time domains imply about constraints on the stellar atmospheric parameters?"

An additional driver is to provide some expectations for wide-field imaging using the next generation of radio telescopes, e.g. the SKA. Radio surveys can provide a large number of unexpected discoveries, revealing different populations of radio emitting objects, a gold mine for successive, more focused radio studies.

For further information on the project, contact Gerry Doyle (jgdat

Last Revised: 2011 December 1st